How does wind affect the drying process of rammed earth walls?

Drying Dynamics

Wind plays a crucial role in the drying process of rammed earth walls, particularly in arid and desert climates. As wind blows over the wall, it carries away moisture from the surface, accelerating the evaporation rate. This can lead to uneven drying, where some areas dry faster than others, resulting in cracking and potential structural damage. In extreme cases, wind-driven evaporation can reduce the wall’s strength and durability.

Formwork Strategies

To mitigate the effects of wind on drying, builders can employ formwork strategies that create a more stable environment for moisture evaporation. One technique is to use a double-forming approach, where a second layer of formwork is added on top of the initial layer to enclose the soil mixture. This helps to reduce wind-driven evaporation by creating a more sheltered environment for the wall to dry. Builders can also use a combination of windbreaks and shading structures to further reduce the impact of wind on drying.

Soil Mix Optimization

In addition to formwork strategies, optimizing the soil mix can also help to reduce the effects of wind on drying. Rammed earth walls with a higher proportion of clay and silt tend to be more resistant to wind-driven evaporation, as these materials have a higher capacity for retaining moisture. Builders can also add small amounts of polymers or other additives to the soil mix to improve its cohesion and reduce shrinkage, further minimizing the risk of cracking and damage.